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X-ray powder diffractometer Bruker D8 (CuKα radiation, SOL-X energy dispersive detector) is used to determine:
We develop and apply the novel computational scheme LDA+DMFT to study materials with correlated electrons from first principles. LDA+DMFT is based on a combination of conventional band-structure methods, e.g., the local density approximation (LDA), with the dynamical mean-field theory (DMFT) for correlated electron systems. This allows us to capture quantum-mechanical and thermal spin, charge and orbital fluctuations and describe correlation driven metal-insulator transitions or formation of various types of long-range order, e.g. Celý text >>
The study is aimed to the development of new hybride nanoparticles for the use for magnetic resonance imaging as contrast materials, local destruction of cancers by the magnetic fluid hyperthermia and DNA diagnostics of microorganisms. It includes the synthesis of magnetic cores, their stabilization in a form of suspensions, ensuing preparation of biocompatible shells suitably modified and a complex characterization employing a number of physical, chemical and biological methods with respect to the expected application. Celý text >>
The cobaltites derived from LaCoO3 are prospective materials for their electronic and catalytic properties and represent also fundamental interest because of the temperature and pressure driven transitions between Co(III) ionic states of different spin numbers. The aim of the project is to investigate novel phenomenon where itinerant charge carriers convert the surrounding diamagnetic Co(III) states into magnetic ones, forming large spin polarons. Celý text >>
The project deals with a fundamental research on novel oxide thermoelectric materials of p-type considered for the electric power generation using waste heat. As concerns the conversion efficiency of such thermoelectric generators, the materials should operate in wide temperature range and keep at the same time a high figure of merit, ZT =(S2R)T, where S is the Seebeck coefficient, R is the ratio of electric resistivity and thermal conductivity and T is the actual temperature of the thermoelectric segment. Celý text >>
The semiconductors based on ZnO doped by magnetic impurities belong to a new class of advanced materials, dilute magnetic semiconductors, which have recently received much experimental and theoretical attention as a suitable spin source for spintronic applications. Some of the highly doped wide band gap materials like (Zn,Mn)O reveal a ferromagnetic like behavior near and above room temperature, which is considered as a major criterium for spintronic applications. Celý text >>
Fast progress in miniaturization of electronic devices requires new approach not only in the technology, producing nanometric and subnanometric objects, but also in their characterization. EMCD – electron magnetic circular dichroism represents a new method, which uses the electron transmission microscope to determine the magnetic moments of atoms from which consists the object investigated. Celý text >>
In many magnetic materials it is possible to change the size of the magnetic moments, typically reduce, by application of pressure. Such transition is usually abrupt and sometimes is accompanied transtion to a metallic state. Using the LDA+DMFT computational scheme we were able to obtain such a behavior in MnO and Fe2O3 in agreement with experimental observations. We have identified the microscopic mechanisms responsible for these transitions and explained the observed changes in the density of the materials accompanying the transition. Celý text >>
Synthesized stable water suspensions of manganese perovskites magnetic nanoparticles of the composition La1-xSrxMnO3 of advantageous properties markedly exceeding the behaviour of the existing commercial products on the basis of iron oxides. They afford higher heating efficiency and simultaneously controlled heating excluding the local overheating risk of a health tissue.
Celý text >>The result of our research is an unified description of the magnetic and electric transitions in cobaltites LnCoO3 (Ln = La, Y, rare earths), associated with thermally activated changes of the spin state of the octahedrally coordinated Co3+ ions, and the determination of the polaron character of the hole and electron carriers in doped cobaltites.
Celý text >>
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